Nate Silver, whose work on his old 538.com blog and now on the New York Times website I admire greatly, has a blogpost on the question—puzzling to him and to many of us—on why Rick Perry decided the morning after his disastrous fifth-place finish in the Iowa caucuses to stay in the race, in South Carolina if not in New Hampshire, rather than bow out, as his cancellation of his travel plans to South Carolina and his return to Texas instead indicated to all of us with any history of observing these things suggested that he would.

Silver advances two scenarios for Perry’s decision. One is personal: pride demands that he keep on fighting. The other is political: his advisers, major donors, conservative leaders all demanded that he keep on.